Apparatus for evaporation



Sept. 8, 1953 Y P. B. sADTLER 25651356 APPARATUS FOR EVAPORATION Filed Aug. 2 5. 194e s sheets-sheet 1 v P. B. SADTLER APPARATUS FOR EVAPORATION slept. s, 1953 3 Sheets-Sheet l2 Filed Aug. 25, 194s` INVENTOR BY 6 ATTRNE 54"( Sept-.8, v1953 P. B. sADTLER 2,651,356

APPARATUS PoR EvAPoRATIoN v Filed Aug. 25,L 194e A s sheets-sheets ATToRN 5 FIG. 8.-

Patented Sept. 8, 1953 UNITED STATES PATENT OFFICE 2,651,356 APPARATUS FOR EVAPORATION Philip B. Sadtler, South Norwalk, Conn., assignor of one-half to Henry M. Hunter, Brooklyn, N. Y., and one-half to George D. Dickey, Ridgewood, N.

Application August 25, 1948, Serial No. 46,147

( Cl. S-17) 5 Claims.

There are certain points in a multiple effect evaporator at which vapors are produ-ced in an economy of the evaporator is improved.

vention and wherein:

Figure 1 is a iow sheet showing diagrammatioally a quintuple elect evaporator incorporating the present invention;

Figure 2 is a side view of one of the heating elements of the evaporator shown in Figure 1 with the end portions of the vheating element shown in vertical section;

Figure 3 is a vertical section through one end portion of the heating element taken on the line 3 3 ofA Figure 2, and showing the partitions that dene the preheating section of the heating element;

Figure 4 is a vertical section through the other end of the heating element taken on the line 4 4 of Figure 2 and further showing the partitioning of the heating element;

Figure 5 is a perspective view of one end of the heating element broken away to show still 'further details of the partitioning;

Figure 6 is a vertical section through a modi- -ed form of the structure of Figure 2 wherein -the heating element is located within an evapo- `rator body;

Figure 7 is a' fragmentary horizontal section vtaken on the line 1 1 of Figure 6 and showing a partition that isolates a preheating section of the heating element of Figure '7, and

Figure 8 is a fragmentary horizontal section taken on the line 8 8 of Figure 6 and further `showing partitions that isolate the preheating section.

ing vthe evaporator bodies Ina and lub and four subsequent eects having the evaporator bodies,

I2, I4, i6 and I8' respectively. `The evaporator bodies are connected by pipes 20a, 20h, 22, 24,

-separated from the liquor and caused to flow on to a subsequent eiect.

Steam to heat the Vapors evolved in the bodies I llal and wb of the rst eifect pass through the branch pipes 12a and 12b respectively, thence through pipe 12 to the heating element 52 of the second effect. In like manner vapors from the bodies l2, |4 and I6 pass through the pipes 14, 16 and 16 respectively, to the heating elements 54, 5.6 and 58 respectively of the third, fourth and fifth effects. Vapors evolved in the fifth etfect pass through the pipe 86 to a condenser 82 wherein they are condensed.

Steam condensate from the heaters aiand 56h is withdrawn through the pipes 84a and 84h respectively, and conductedto axsuitablepoint of disposal. Condensate from fthe heating elements 52, 54 and 56 is conducted by pipes 86, 88 and 9|) respectively, to the shell sides of heating elements 54, 56 and 5B respectrvielypto take advantage of such flash evaporation as may .nccur at the successively lower pressures existing within successive heating elemen Condensate from heating element '58 iswithdrawn through pipe 92 Vand pumped bya pump 84 to a 'suitable point of disposal.

The liquor to be evaporated is fed to the 'third effectof the evaporator and more particularly is introduced into the pipe '24 from va feed pipe 66. Liquor is transferred from the evaporator body I4 to the body |6 through apipe 98, .and from the body |6 to the body I6 through apipe |66. Since the evaporator bodies 14, `|6 t3' operate at successively lower pressures, 'no pump is required to effect these transfers.

The liquor from the fifth eiecto'f the'evaporator is transferred to the second effect, and in accordance with the present 'invention this liquor is preheated-before'being introduced into the second effect by being passed through the same heating elements in'whichit was' previously heated for purposes of vaporization. Themternal structure of the heating elementsthat permits the preheating and vaporiziug steps to be carried out simultaneously in the same apparatus is described morefully hereafter.

Liquor is withdrawnfromevapcrator body 18 through a pipe `through pipe |06'to the heater'iBi-wherein'it is partially preheated. Fromheater "58 this transfer liquor passes successively through pipe |68, heating element 56, :pipe |69, heating element 54 and pipe H6 tothe pipe-22 of thecirculating system ofthe second effect.

Liquor is transferred-from-evaporator body i2 to body lsb throughppe |2, pump liland pipe H6, and from'body lb tobody'la through pipe H8, pump |26 and pipe |22. The concentrated liquor from body lua flows through pipe |24 to a flash chamber |26 wherein flash'evaporation occurs. Vapors from the ash chamber |26, which comprise the excess vapors previously referred to, are available for preheating vthe liquor and are conducted by pipe |28 to the vapor pipe 14 through which they flow to the heating element 54. The concentrated liquor is withdrawnY from chamber |26 through pipe |36 and pumped by pump |32 .to a suitable point of disposal.

The preheating inthe heating elements 58, 56 and 54 of the liquor transferred from body |8 of the fifth effect to body l2 of the second effect is an important feature of the present invention. The arrangement vis such that excess heat available in the vapors supplied to kthese heating elements is utilized to raise the ternperature of the liquor substantially to its boiling point and thus the thermal eiiiciency of the evaporator is materially increased. Also since the preheating is' carried out in the same heatand ing element that supplies heat for vaporization, the heating surface of the heating element is more eiiiciently used and hence a smaller heat transfer area can capacity. Moreover, the equipment cost is substantially less than it would be if, for example, separate heating elements were provided.

The heating elements 54, 56 and 58 may be nsimilarly constructed and the construction of one of these `elements is shown in Figures 2-5 of the drawing. Referring to Figures 2 5, the heating element there vshown comprises a cylindrical casing in'which the spaced tube sheets |42 and |44 are ,mounted and support the tubes of a tube bundle |46 in the usual manner. The

casing |40 `has* the usual vapor connection |4| and condensate connection |43. At its opposite ends the heating element isprovided with the heads |48 and |56 that enclose the ends of tubes |46.

Aspreviously indicated the heating element has formed therein vpartitions that effectively divide the Vtube bundle |46 into a vaporizing section and a preheating section. Referring particularly to Figures 3 and 5, within the head |48 there is a partition |56 that extends from the outer end of the head to the tube sheet |42 and effectively isolates a relatively small segment of the tube bundle |46 as a preheating section. The remainder of the tube bundle, comprising a major fraction of the tubes, constitutes the vaporizing vsection of the heating element and communicates with a chamber |5| defined by head |48, tubes'heet |42 and partition |56. l

As shown in Figure 5 the partition |56 is mounted 'at its inner end in a channel-shaped member |56 that is preferably made of a resilient material, such as rubber, to provide an adequate seal and prevent liquid communication between the preheating section and the vaporiz'ing section of the tube bundle. The preheating section is internally divided by the partitions |52 'and |54 that extend from the partition |56 to the `side wall 'of l'head |48 and denne three chambers |64, |65 and |66 communicating with separate banks of tubes of the preheating section. The chamber |66 is provided with an inlet connection |66 and the chamber |64 is provided with a discharge connection |62.

v'Referring to "Figure '4 the head |50 at 'the opposite 'end of the heating element is provided vwith a partition |68 that is similar 'to the'partition |56 and with a second partition |69 'that extends horizontally across the diameter of the heating element. 'The partitions |68 and |69 dividethe space within head |50 into an upper chamber |16 and lower chamber |1| communi- 'catingwith the vaporizing section of the heating element and into an upper chamber |12 and lower chamber |13 communicating with the preheating section of the heating element. The chamber is provided with an inlet connection |14 'and the chamber |16 is provided with a discharge connection |15.

The construction is such that the preheated liquor makes fourA passes through the tube bundle, whereas vthe liquor to be vaporized makes only Ytwo passes through the tube bundle. The liquor to be vaporized enters the chamber |1| through inlet |14 and because of the partition or baiiie |69is directed through the tubes of the lower portion of the vaporizing section to the chamber |5| at the opposite end of the heating element. This liquor then returns through the 'tubes of the upper portion of the vaporizing section to the chamber |10 and leaves the heating element through connection |15.

The liquor to be preheated enters the chamber |66 through connection |60 and is directed by partition or bafiie |54 into the lowermost group of tubes of the preheating section through which it fiows to the chamber |13. From chamber |13 the liquor flows back through a second bank of tubes to chamber |65, thence through a third bank of tubes to chamber |12, and a fourth bank of tubes to chamber |64, whence it leaves the heating element through discharge connection |62. y

The method and apparatus of the present invention may also be used in evaporators of the type wherein the heating element is mounted within the evaporator body, and a structure of this sort is shown in Figures 6-8 of the drawings. Referring to these figures, the numeral |80 designates the casing of an evaporator body within which is mounted in the usual manner a pair of spaced tube sheets |82 and |84 supporting the tubes of a tube bundle |86. The lower ends of tubes |86 are enclosed by a head |88 that cooperates with the tube sheet |84 to define a space which is divided by the partitions |90 and |92 into three chambers |94, |96 and |98.

At the top of the tube bundle |86 a cap or head 200 cooperates with the tube sheet |82 to .dene

a chamber 202 in such manner as to isolate a segment of the tubes of the tube bundle I 88 from the remainder of the tubes. The head 209 is held against the tube sheet |82 by a support 204 that is fixed to the casing |80 of the evaporator body. A conventional curved baffle 206 is mounted in the usual manner above the upper ends of tube |86. The partitions |90 and |92 and the head 200 serve to divide the tube bundle into a preheating section and a vaporizing section.

The liquor to be evaporated enters the chamber |94 through an inlet connection 208 and flows upwardly through the tubes of the vaporizing section of the tube bundle |86. Steam is supplied to the outer surfaces of tubes |86 through L a steam inlet connection 2|0 and condensate is removed through a condensate discharge connection 2|2. The liquor from chamber |94 is heated and partially vaporized Within the tubes as it flows upwardly therethrough. Upon leaving the tubes the vapor and liquor are separated and the vapor passes into the upper portion of the evaporator body, whereas the liquor is withdrawn through a discharge connection 2|4. The baiile 206 assists in preventing entrainment of liquor with the vapors.

The liquor to be preheated enters chamber |95 through an inlet connection 2|6 and fiows upwardly through the bank of tubes that communicates with chamber |96. At the top of the tube bundle the preheated liquor iiows through chamber 202 and downwardly through a second bank of tubes to chamber |98, whence it is withdrawn through a discharge connection 2 8. Thus with the construction shown, separate portions of liquor may be vaporized and preheated in the single heating element of the evaporator body.

From the above description it should be apparent that the present invention provides a novel method and apparatus for achieving the objects set forth above. Excess heating vapors available within the evaporator are utilized to preheat the liquor, and the preheating is carried out in the saine preheating element in which the main bodies of liquor are vaporized. By carrying out both heating steps in the same piece 'of equipment, unusually effective utilization of heat transfer area is achieved and substantial economies in the cost of equipment are effected.

Since many embodiments might be made of the present invention and since many changes might be made in the embodiment disclosed herein, it is to be understood that the foregoing description is to be interpreted as illustrative only and not in a limiting sense.

I claim:

1. An evaporator effect adapted to be incorporated in a multiple-effect evaporator comprising in combination, an evaporator body, a tube"- in-shell heating element, the end portions of said heating element being provided with partitions to divide said heating element effectively into a vaporizing section and a preheating section to provide for simultaneously preheating and vaporizing distinct bodies of liquor within said heating element, a first and second conduit interconnecting spaced points near the bottom of said evaporator body with spaced points in the vaporizing section of said heating element to establish a closed circulating system including said evaporator body and said vaporizing section, a pump located in said circulating system for circulating liquor therethrough, a third conduit interconnecting a third spaced point near the bottom of said evaporator body and the preheating section of said heating element, and a pump located in said third conduit for withdrawing liquor from said evaporator body and pumping it to and through said preheating section of said heating element.

2. A multiple effect evaporator of the mixed flow type, comprising in combination, a, first group of effects connected for countercurrent ow of liquor and vapor, a second group of effects connected for concurrent ow of liquor and vapor, each of said effects including an evaporator body, a heat exchanger and a pump connected to circulate liquor from said evaporator body through said heat exchanger back to said evaporator body, at least one of said heat exchangers of said second group of effects being provided with internal partition means dividing said exchanger into a main heating zone wherein said circulating liquor is heated and a preheating zone, and a liquor conduit interconnecting an effect of said second group with an effect of said first group, said conduit including the preheating zone of said one heat exchanger whereby liquor owing through said conduit from said second group of effects is preheated before reaching said first group of effects.

3. A multiple effect evaporator of the mixed flow type, comprising in combination, a first group of effects connected for countercurrent flow of liquor and vapor, la second group of effects connected for concurrent flow of liquor and vapor, each of said effects including an evaporator body, a heat exchanger and a pump connected to circulate liquor from said evaporator body through said heat exchanger back to said evaporator body, each of said heat exchangers of said second group of effects being provided with internal partition means dividing said exchanger into a main heating zone wherein said circulating liquor is heated and a preheating zone, and a liquor conduit interconnecting an effect of said second group with an effect of said first group, said conduit including the preheating zone of each of said heat exchangers whereby liquor flowing through said conduit from said second group cf eifectsis preheated before reaching said nrst group of `eiects.

4. AA multiple effect evaporator of the mixed flow type, vcomprising in combination, a first group of eects connected for countercurrent flow of liquor and vapor, a second group of eiects connected for concurrent flow of liquor and vapor, each of said eiects including an evaporator body, a heat exchanger and a pump connected to circulate liquor from said evaporator body through said heat exchanger back to said evaporator-body, each of said heat exchangers of said second group of effects being provided with internal partition means dividing said exchanger into a main heating zone wherein said circulating liquor is heatedand a preheating zone, and a liquor conduit interconnecting the last effect of said second group with the last effect of said rst group and including a liquor transfer pump and the preheating zone of each of said internally divided heat exchangers whereby liquor from the last effect of said second group is preheated before passing through the last effect of said rst group.

5. A multiple effect evaporator of the -mixed flow type, comprising in combination, a rst group of effects connected for countercurrent now of liquor and vapor, a second group of effects connected for concurrent new of liquor and vapor, each of said effects including an evaporator body, a heat exchanger and a pump connected to circulate liquor from said evaporator body through said heat exchanger back to said evaporator body, each of said heat exchangers of said second group -and a Ypreheating zone,

-of effects being provided with internal -partition means dividing said exchanger into a mainheatin g zone wherein said circulating liquor Vis heated and aliquor conduit interconnecting the last effect of said second group with the last `eiect of said rst group, said conduitincluding -a liquor transfer pump and the preheating zone of -each of vsaid heat exchangers, vsaid preheating zones being connected into said conduitin series relation, whereby liquor leaving the last Yeffect of saidsecond group of effects ows first through the preheating zone of the heat exchanger of said last effect and then successively through the lpreheating zones of the heat exchangers of successive preceding effects of said second group before passing to the last effect of said rstgroupof effects.

PHILIP B. SADTLER.

References Citedn the nle or this ,patent UNITED ,STATES VPUJITENIS 

